The field of the disclosure relates generally to gas bearings, and more particularly, to gas bearings for turbine engines.
The inventors have observed that in conventional turbine engine configurations separate components coupled to a common shaft may require different rotational speeds to perform a desired function. For example, a turbine may have a required rotational speed that is significantly higher that a required rotational speed of a fan. To accommodate for this difference in speed a gearbox may be utilized between the fan and low pressure turbine to allow each of the components to operate at different speeds. However, when operating the low pressure turbine rotor system at higher speeds enabled by the presence of the gearbox the low pressure turbine rotor will most likely need to operate at supercritical speeds. Operating above this speed may increase shaft bending stresses and dynamic bearing loads, which may result in excessive wear, or premature failure of components of the engine. The inventors have observed that such negative effects may be compensated for by utilizing a shaft having a higher stiffness. However, to achieve the requisite stiffness a prohibitive increase in diameter and weight of the shaft would be required.
Therefore, the inventors have provided a differential gas bearing for turbine engines.